1. Field of the Invention
This invention relates to a method for positioning and securing components of a workpiece and more particularly to a method for positioning and securing a pair of workpiece components where one of the workpiece components is maintained in a predetermined spacial relation with another workpiece component while the workpiece components are secured to each other by welding or the like.
2. Description of the Prior Art
Devices for positioning workpiece components for securing the components in a preselected manner is well known in the art. For example, U.S. Pat. No. 2,787,700 illustrates and discloses a work feeding and positioning mechanism for feeding a part or component to two operative positions relative to a pair of welding electrodes. A carriage is reciprocated toward and away from the welding electrodes and includes a work holder for carrying a component to and accurately positioning the component between the electrodes for welding of a pair of contacts thereon. The work holder is mounted on the carriage for transverse movement thereof. The length of the transverse movement of the work holder on the carriage is adjustable whereby the work holder accurately locates the part successively in two positions while the two contacts are sequentially welded thereto in a predetermined spaced relation to each other.
U.S. Pat. No. 1,714,867 discloses a welding apparatus adapted for use in construction of sheet metal shells and particularly internally trussed sheet metal doors. The trussed sheet metal doors include a truss structure first welded to a back plate and the truss structure is welded to a front plate. The back plate is placed on a table between rails and the trussed structure is placed on top of the back plate. The rails are adjusted and secured by bolts to permit the door to be moved between the rails. A main feed mechanism positions the door in respect to the electrodes for the first spot welding operation. A lower electrode remains fixed while an upper electrode is manually operated to move into position relative to the lower electrode for forming the spot weld operation of the welding mechanism. The operation is sequential in that the sheet metal door members are first initially moved to a position with respect to the electrodes followed by the step of clamping the back plate and trussed structure together by the movement of the upper electrode in respect to the lower electrode. With the members in a predetermined position, a row of spot welds are made along the length of the door at a preselected distance from each other. After one row of spot welds are made, the door is moved to a position for making a second row of spot welds.
U.S. Pat. No. 1,464,207 discloses an assembling and welding jig for assembling and electrically welding the parts of automobile bodies. A positioning member is operable to position a cowl panel and hold it correctly positioned with reference to the framework of the jig and body frame members to which it is to be welded. The positioning member is arranged to be swung into and out of operative position to permit the removal of the body frame and cowl from the welding jig and the insertion of another body frame and cowl panel to be connected together.
While it has been suggested by the prior art devices to move a pair of components into a preselected positioning for fastening together as by welding or the like, the prior art devices require the components to be moved by a carrier type mechanism into a predetermined position relative to the welding machine that remains fixed relative to the components. Once the components are located in the predetermined position, the electrodes of the welding machine are moved into an operative position with respect to the components for welding. This arrangement is cumbersome and is not readily adaptable to welding and other fastening operations where movement of the welding machine from place to place to carry out the welding operation is required.
Portable spot welders are known, such as illustrated and described in U.S. Pat. Nos. 2,441,438 and 2,535,946. The spot welders disclosed in these patents are designed to be manually moved from place to place to perform spot welding operations. The portable spot welder includes a pair of electrodes or tongs in which welding tips are provided at the end of the tongs and are adapted to be pressed toward each other against the components of a workpiece disposed therebetween. A lower tong is fixed, and an upper tong is pivotally connected to a cap of the welder to be moved by a toggle mechanism into contact with one surface of the workpiece.
With the above described portable spot welding apparatus, the workpiece components must be initially positioned in a predetermined relationship to each other for spot welding. Generally, this is done manually and with the aid of clamps or other devices to secure the components together before they can be welded. Not only is this operation time consuming, but requires a number of operating personnel.
Therefore, there is a need for a method to position and secure the components of a workpiece by means of a fastening device such as a spot welder and the like where the fastening device is readily movable from place to place to provide for precise positioning of the components relative to the welding or fastening machine in an efficient manner that reduces the time for the fastening of the components to be made and the number of operating personnel to carry out the spot welding operation.